Intra- and postoperative complications of navigated and conventional techniques in percutaneous iliosacral screw fixation after pelvic fractures: Results from the German Pelvic Trauma Registry

Background: Percutaneous iliosacral screw placement following pelvic trauma is a very demanding technique involving a high rate of screw malpositions possibly associated with the risk of neurological damage or inadequate stability. In the conventional technique, the screw’s correct entry point and the small target corridor for the iliosacral screw may be difficult to visualise using an image intensifier. 2D and 3D navigation techniques may therefore be helpful tools. The aim of this multicentre study was to evaluate the intra- and postoperative complications after percutaneous screw implantation by classifying the fractures using data from a prospective pelvic trauma registry. The a priori hypothesis was that the navigation techniques have lower rates of intraoperative and postoperative complications. Methods: This study is based on data from the prospective pelvic trauma registry introduced by the German Society of Traumatology and the German Section of the AO/ASIF International in 1991. The registry provides data on all patients with pelvic fractures treated between July 2008 and June 2011 at any one of the 23 Level I trauma centres contributing to the registry. Results: A total of 2615 patients were identified. Out of these a further analysis was performed in 597 patients suffering injuries of the SI joint (187 � with surgical interventions) and 597 patients with sacral fractures (334 � with surgical interventions). The rate of intraoperative complications was not significantly different, with 10/114 patients undergoing navigated techniques (8.8%) and 14/239 patients in the conventional group (5.9%) for percutaneous screw implantation (p = 0.4242). Postoperative complications were analysed in 30/114 patients in the navigated group (26.3%) and in 70/239 patients (29.3%) in the conventional group (p = 0.6542). Patients who underwent no surgery had with 66/197 cases (33.5%) a relatively high rate of complications during their hospital stay. The rate of surgically-treated fractures was higher in the group with more unstable Type-C fractures, but the fracture classification had no significant influence on the rate of complications. Discussion: In this prospective multicentre study, the 2D/3D navigation techniques revealed similar results for the rate of intraoperative and postoperative complications compared to the conventional technique. The rate of neurological complications was significantly higher in the navigated group.

The Quiet Eye and motor performance – Introducing fixation duration as an independent variable

Evidence suggests a strong relation between superior motor performance and the duration of the last fixation before movement initiation (called Quiet Eye, QE). Although this phenomenon proves to be quite robust, to date, only little is known about its functional role. Therefore, in two experiments, a novel paradigm is introduced, testing the QE as independent variable by experimentally manipulating the duration of the last fixation in a throwing task. In addition, this paradigm allowed for the manipulation of the predictability of the target position. Results of the first study revealed an increase in throwing accuracy as function of experimentally prolonged QE durations. Thus, the assumption that the QE does not surface as a mere by-product of superior performance could be confirmed. In the second study, this dependency was found only under high task-demand conditions in which the target position was not predictable. This finding confirms the hypothesis that it is the optimization of information processing which serves as the crucial mechanisms behind QE effects.

Urethral entrapment following pelvic fracture fixation in a dog

An 18-month-old female crossbred dog was presented with a unilateral sacroiliac luxation and separation of the pelvic symphysis. Surgical correction of the luxation with screw fixation led to entrapment of the urethra between the symphyseal parts of the two hemipelves.

Surgical anatomy of the feline sacroiliac joint for lag screw fixation of sacroiliac fracture-luxation

Twenty-eight feline pelves (56 hemipelves) were examined in order to identify the location for optimal sacroiliac screw placement in sacroiliac fracture-luxation repair. A drill hole was started on the median plane of the hemipelvis in the centre of the body of the first sacral segment until it penetrated the lateral cortex of the ilial wing, thus providing optimal drill hole placement. The position of the drill hole on the articular surface of the sacral wing and on the lateral surface of the ilial wing was measured. The distance of the drill hole from the cranial margin of the sacral wing was 51% of sacral wing length, just cranial to the crescent shaped hyaline cartilage. The distance from the dorsal margin was 47% of sacral wing height. The drill bit direction has to be adjusted to the cranio-caudal inclination (range 10° to 29°) and dorso-ventral inclination (range 2° to 25°) of the sacral wing. A notch in the cranial edge of the sacral wing was present, with variable position, in 34% of the specimens and is consequently not a useful landmark for sacroiliac screw placement. The drill hole on the lateral surface of the ilium was located in craniocaudal direction at a distance of 69% of sacral tuber length, measured from the cranial dorsal iliac spine. The dorso-ventral position of the drill hole was at a distance of 52% of ilial wing height measured from the sacral tuber. The ventral gluteal line, present in 93% of the cases, is a useful landmark to locate optimal screw hole position on the ilial wing.

Comparison of theoretical fixation stability of three devices employed in medial opening wedge high tibial osteotomy: a finite element analysis.

BACKGROUND Medial open wedge high tibial osteotomy is a well-established procedure for the treatment of unicompartmental osteoarthritis and symptomatic varus malalignment. We hypothesized that different fixation devices generate different fixation stability profiles for the various wedge sizes in a finite element (FE) analysis. METHODS Four types of fixation were compared: 1) first and 2) second generation Puddu plates, and 3) TomoFix plate with and 4) without bone graft. Cortical and cancellous bone was modelled and five different opening wedge sizes were studied for each model. Outcome measures included: 1) stresses in bone, 2) relative displacement of the proximal and distal tibial fragments, 3) stresses in the plates, 4) stresses on the upper and lower screw surfaces in the screw channels. RESULTS The highest load for all fixation types occurred in the plate axis. For the vast majority of the wedge sizes and fixation types the shear stress (von Mises stress) was dominating in the bone independent of fixation type. The relative displacements of the tibial fragments were low (in μm range). With an increasing wedge size this displacement tended to increase for both Puddu plates and the TomoFix plate with bone graft. For the TomoFix plate without bone graft a rather opposite trend was observed.For all fixation types the occurring stresses at the screw-bone contact areas pulled at the screws and exceeded the allowable threshold of 1.2 MPa for at least one screw surface. Of the six screw surfaces that were studied, the TomoFix plate with bone graft showed a stress excess of one out of twelve and without bone graft, five out of twelve. With the Puddu plates, an excess stress occurred in the majority of screw surfaces. CONCLUSIONS The different fixation devices generate different fixation stability profiles for different opening wedge sizes. Based on the computational simulations, none of the studied osteosynthesis fixation types warranted an intransigent full weight bearing per se. The highest fixation stability was observed for the TomoFix plates and the lowest for the first generation Puddu plate. These findings were revealed in theoretical models and need to be validated in controlled clinical settings.

Evaluation of colon cancer histomorphology: a comparison between formalin and PAXgene tissue fixation by an international ring trial.

The aim of our study was to evaluate the quality of histo- and cytomorphological features of PAXgene-fixed specimens and their suitability for histomorphological classification in comparison to standard formalin fixation. Fifteen colon cancer tissues were collected, divided into two mirrored samples and either formalin fixed (FFPE) or PAXgene fixed (PFPE) before paraffin embedding. HE- and PAS-stained sections were scanned and evaluated in a blinded, randomised ring trial by 20 pathologists from Europe and the USA using virtual microscopy. The pathologists evaluated histological grading, histological subtype, presence of adenoma, presence of lymphovascular invasion, quality of histomorphology and quality of nuclear features. Statistical analysis revealed that the reproducibility with regard to grading between both fixation methods was rather satisfactory (weighted kappa statistic (k w) = 0.73 (95 % confidence interval (CI), 0.41-0.94)), with a higher agreement between the reference evaluation and the PFPE samples (k w = 0.86 (95 % CI, 0.67-1.00)). Independent from preservation method, inter-observer reproducibility was not completely satisfactory (k w = 0.60). Histomorphological quality parameters were scored equal or better for PFPE than for FFPE samples. For example, overall quality and nuclear features, especially the detection of mitosis, were judged significantly better for PFPE cases. By contrast, significant retraction artefacts were observed more frequently in PFPE samples. In conclusion, our findings suggest that the PAXgene Tissue System leads to excellent preservation of histomorphology and nuclear features of colon cancer tissue and allows routine morphological diagnosis.

Plate fixation of extra-articular fractures of the proximal phalanx: do new implants cause less problems?

BACKGROUND Limited range of finger motion is a frequent complication after plate fixation of phalangeal fractures. The purpose of this study was to evaluate the results of plate fixation of extra-articular fractures of the proximal phalanx using current low-profile mini-fragment-systems. METHODS From 2006 to 2012, 32 patients with 36 extra-articular fractures of the proximal phalanx of the triphalangeal fingers were treated with open reduction and plate fixation (ORPF) using 1.2 and 1.5 mm mini-fragment systems. Patients presenting with open fractures grade 2 and 3 or relevant laceration of adjacent structures were excluded from the study. We retrospectively evaluated the rate of mal-union or non-union after ORPF, the need for revision surgery, for plate removal, and for tenolysis. Data were analyzed for further complications with regard to infections or complex regional pain syndrome (CRPS). RESULTS No infections were noted. Five patients developed transient symptoms of CRPS. Six weeks postoperatively, total active finger motion (TAM) averaged 183°, and all 32 patients underwent formal hand therapy. At the latest follow-up or at the time of plate removal, respectively, the mean TAM improved to 213°. Extension lag of proximal interphalangeal joints was found in 67 % of all fractured fingers. Secondary surgery was necessary in 14 of 32 patients (2 corrective osteotomies, 12 plate removals including 7 procedures explicitly because of reduced mobility). CONCLUSIONS Despite of new implant designs significant problems persist. Adhesions of extensor tendons leading to limited range of finger motion are still the most frequent complications after ORPF of proximal phalangeal fractures, even in absence of significant soft-tissue damage. LEVEL OF EVIDENCE Therapeutic, Retrospective, Level IV.

Post mortem computed tomography and core needle biopsy in comparison to autopsy in eleven bernese mountain Dogs with histiocytic sarcoma

Background: Bernese mountain dogs are reported to have a shorter life expectancy than other breeds. A Major reason for this has been assigned to a high tumour prevalence, especially of histiocytic sarcoma. The efforts made by the breeding clubs to improve the longevity with the help of genetic tests and breeding value estimations are impeded by insufficiently reliable diagnoses regarding the cause of death. The current standard for post mortem examination in animals is performance of an autopsy. In human forensic medicine, imaging modalities, such as computed tomography and magnetic resonance imaging, are used with increasing frequency as a complement to autopsy. The present study investigates, whether post mortem computed tomography in combination with core needle biopsy is able to provide a definitive diagnosis of histiocytic sarcoma. For this purpose we have analysed the results of post mortem computed tomography and core needle biopsy in eleven Bernese mountain dogs. In the subsequent autopsy, every dog had a definitive diagnosis of histiocytic sarcoma, based on immunohistochemistry. Results: Computed tomography revealed space-occupying lesions in all dogs. Lesion detection by post mortem computed tomography was similar to lesion detection in autopsy for lung tissue (9 cases in computed tomography / 8 cases in autopsy), thoracic lymph nodes (9/8), spleen (6/7), kidney (2/2) and bone (3/3). Hepatic nodules, however, were difficult to detect with our scanning protocol (2/7). Histology of the core needle biopsies provided definitive diagnoses of histiocytic sarcoma in ten dogs, including confirmation by immunohistochemistry in six dogs. The biopsy samples of the remaining dog did not contain any identifiable neoplastic cells. Autolysis was the main reason for uncertain histological diagnoses. Conclusions: Post mortem computed tomography is a fast and effective method for the detection of lesions suspicious for histiocytic sarcoma in pulmonary, thoracic lymphatic, splenic, osseous and renal tissue. Optimization of the procedure regarding the scanning protocol and tissue sample size and number will improve the accuracy of the method. Keywords: Post mortem computed tomography, Core needle biopsy, Bernese mountain dog, Histiocytic sarcoma, Autopsy

Treatment of posttraumatic cubitus varus in children and adolescents. Supracondylar humeral osteotomy using radial external fixation

OBJECTIVE Precise adaptable fixation of a supracondylar humerus osteotomy with a radial/lateral external fixator to correct posttraumatic cubitus varus. INDICATIONS Acquired, posttraumatic cubitus varus as a result of a malhealed and unsatisfactorily treated supracondylar humerus fracture. Idiopathic, congenital cubitus varus (very seldom) if the child (independent of age and after complete healing) is cosmetically impaired; stability of the elbow is reduced due to malalignment (hyperextension); secondary problems and pain (e. g., irritation of the ulnar nerve) are expected or already exist; or there is an explicit wish of the child/parents (relative indication). CONTRAINDICATIONS In principle there are no contraindications provided that the indication criteria are filled. The common argument of age does not represent a contraindication in our opinion, since angular remodeling at the distal end of the humerus is practically nonexistent. SURGICAL TECHNIQUE Basically, the surgical technique of the radial external fixator is used as previously described for stabilization of complex supracondylar humeral fractures. With the patient in supine position, the arm is placed freely on an arm table. Using a 4-5 cm long skin incision along the radial, supracondylar, the extracapsular part of the distal humerus is prepared, whereby great caution regarding the radial nerve is advised. In contrast to the procedure used in radial external fixation for supracondylar humeral fracture treatment, two Schanz screws are always fixed in each fragment at a distance of 1.5-2 cm. The osteotomy must allow the fragment to freely move in all directions. The proximal and distal two Schanz screws are then connected with short 4 mm carbon or stainless steel rods. These two rods are connected with each other over another rod using the tub-to-tub technique. Now the preliminary correction according the clinical situation can be performed and the clamps are tightened. Anatomical axis and function are checked. If these are radiologically and clinically perfect, all clamps are definitively tightened; if the alignment or the function is not perfect, then further adjustments can be made. POSTOPERATIVE MANAGEMENT Due to the excellent stability, further immobilization not necessary. Immediate functional follow-up treatment performed according to pain. RESULTS Adequate healing is usually expected within 6 weeks. At this time the external fixator can be removed in the fracture clinic. Because the whole operation is performed in an extraarticular manner and the mobility of the elbow is not affected, deterioration of function has never been observed. Also regarding the cosmetic/anatomical situation, good results are expected because they were already achieved intraoperatively.

Real-Time In Vivo Characterization of Primary Liver Tumors With Diffuse Optical Spectroscopy During Percutaneous Needle Interventions: Feasibility Study in Woodchucks

OBJECTIVE This study presents the first in vivo real-time optical tissue characterization during image-guided percutaneous intervention using near-infrared diffuse optical spectroscopy sensing at the tip of a needle. The goal of this study was to indicate transition boundaries from healthy tissue to tumors, namely, hepatic carcinoma, based on the real-time feedback derived from the optical measurements. MATERIALS AND METHODS Five woodchucks with hepatic carcinoma were used for this study. The woodchucks were imaged with contrast-enhanced cone beam computed tomography with a flat panel detector C-arm system to visualize the carcinoma in the liver. In each animal, 3 insertions were performed, starting from the skin surface toward the hepatic carcinoma under image guidance. In 2 woodchucks, each end point of the insertion was confirmed with pathologic examination of a biopsy sample. While advancing the needle in the animals under image guidance such as fluoroscopy overlaid with cone beam computed tomography slice and ultrasound, optical spectra were acquired at the distal end of the needles. Optical tissue characterization was determined by translating the acquired optical spectra into clinical parameters such as blood, water, lipid, and bile fractions; tissue oxygenation levels; and scattering amplitude related to tissue density. The Kruskal-Wallis test was used to study the difference in the derived clinical parameters from the measurements performed within the healthy tissue and the hepatic carcinoma. Kurtoses were calculated to assess the dispersion of these parameters within the healthy and carcinoma tissues. RESULTS Blood and lipid volume fractions as well as tissue oxygenation and reduced scattering amplitude showed to be significantly different between the healthy part of the liver and the hepatic carcinoma (P < 0.05) being higher in normal liver tissue. A decrease in blood and lipid volume fractions and tissue oxygenation as well as an increase in scattering amplitude were observed when the tip of the needle crossed the margin from the healthy liver tissue to the carcinoma. The kurtosis for each derived clinical parameter was high in the hepatic tumor as compared with that in the healthy liver indicating intracarcinoma variability. CONCLUSIONS Tissue blood content, oxygenation level, lipid content, and tissue density all showed significant differences when the needle tip was guided from the healthy tissue to the carcinoma and can therefore be used to identify tissue boundaries during percutaneous image-guided interventions.

Anterior fixation of unstable pelvic ring fractures using the modified Stoppa approach: mid-term results are independent on patients' age

PURPOSE Open surgical management of unstable pelvic ring injuries has been discussed controversially compared to percutaneous techniques in terms of surgical site morbidity especially in older patients. Thus, we assessed the impact of age on the outcome following fixation of unstable pelvic ring injuries through the modified Stoppa approach. METHODS Out of a consecutive series of 92 patients eligible for the study, 63 patients (mean age 50 years, range 19-78) were evaluated [accuracy of reduction, complications, failures, Majeed-Score, Oswestry Disability Questionnaire (ODI), Mainz Pain Staging System (MPSS)] at a mean follow-up of 3.3 years (range 1.0-7.9). Logistic multivariate regression analysis was performed to assess the outcome in relation to increasing patient age and/or Injury Severity Score (ISS). RESULTS Out of 63 patients, in 36 an "anatomic" reduction was achieved. Ten postoperative complications occurred in eight patients. In five patients, failure of fixation was noted at the anterior and/or posterior pelvic ring. In 49 patients, an "excellent" or "good" Majeed-Score was obtained; the mean ODI was 14 % (range 0-76 %); 50 patients reported either no or only minor chronic pelvic pain (MPSS). Only an increasing ISS conferred an increased likelihood of the occurrence of a non-anatomical reduction, a "poor" or "fair" Majeed-Score, or an ODI >20 %. CONCLUSIONS Increasing age did not impact the analysed parameters. Open reduction and internal fixation of the anterior pelvic ring through a modified Stoppa approach in unstable pelvic ring injuries did not result in an unfavourable outcome with increasing age of patients.